arXiv:2511.14581physics.flu-dynastro-ph.EP2025-11

用在线学习方法训练湍流模型,1次周转时间即可预测长期动力学。

Online learning of subgrid-scale models for quasi-geostrophic turbulence in planetary interiors

  • 基于可微分求解器,实现湍流模型在线端到端训练。
  • 仅用1次周转时间数据,准确复现能量谱与喷流迁移等长期行为。
  • 适用于行星内部旋转流模拟,超越传统方法的分辨率限制。

机器学习在大气与海洋的亚网格尺度(SGS)建模中已广泛应用,其中在线端到端学习因可微分求解器参与训练而表现突出。然而现有研究多限于理想化周期域,缺乏机械边界,难以模拟行星内部相关的有界旋转流。本文研究快速旋转环形有界域中的二维准地转湍流,考察三种几何与旋转率配置。系统呈现急流、罗斯贝波等特征,在球壳几何下还存在喷流缓慢的准周期向内漂移。通过构建该系统的可微分求解器,我们使用直接数值模拟的粗粒度数据,在一个周转时间内训练了SGS模型。所有情况下,训练仅需1个周转时间,即可准确复现全局积分诊断、能量谱以及超过训练窗口一个数量级的长期动力学行为(如喷流迁移)。在线训练模型优于经典超扩散和莱斯闭合方案,后者降低径向分辨率后性能急剧下降。该方法大幅提升计算效率,为超越直接数值模拟极限的长期地球物理流体过程研究开辟可能。

原文摘要 · Abstract (English)

Machine learning approaches to subgrid-scale (SGS) modelling are now well established in atmospheric and oceanic applications. Among these, online end-to-end learning, where the differentiable solver participates in the training, has shown particular promise. Yet, existing studies are largely restricted to idealised periodic domains, with no mechanical boundaries, precluding them from addressing the dynamics of bounded rotating flows relevant to planetary interiors. Here we consider two-dimensional quasi-geostrophic turbulence in a rapidly rotating annular bounded domain. We examine three configurations varying the geometry of the container and the rotation rate. The system exhibit key features such as zonal jets, Rossby waves, and, in the spherical shell geometry, a slow quasi-periodic inward drift of the jets. The spectral properties of the zonal and non-zonal flow can be understood in the framework of zonostrophic turbulence theory. We develop a differentiable solver for this system, which allows us to train SGS models online, over a time span of one turnover time, using coarse-grained data from direct numerical simulations. In all cases, a SGS model trained on a single turnover time accurately reproduce global integrated diagnostics, energy spectra as well as long-term dynamical behaviours ---such as jet migration--- occurring on timescales which exceed the training window by one order of magnitude. The online-trained model further outperforms classical hyperdiffusivity and Leith closure schemes, for which reducing the radial resolution is impractical. The resulting speed-up paves the way to further investigations of long-term geophysical fluid processes beyond the reach of direct numerical simulations.

湍流建模在线学习行星流体可微分求解器

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